Fast h264 encoding settings?

[lubczyk]

Fast h264 encoding settings?

I just want to encode my anime quickly so that I can get ti doen faster. I don't mind a bigger filesize if the quality doesn't degrade too much. This is the commandline that I get from megui:

program --crf 16.0 --level 4.1 --ref 5 --mixed-refs --no-fast-pskip --bframes 3 --weightb --deblock 1:2 --subme 5 --partitions p8x8,b8x8,i4x4,i8x8 --8x8dct --ipratio 1.1 --pbratio 1.1 --vbv-bufsize 24000 --vbv-maxrate 24000 --qcomp 0.5 --me umh --merange 12 --threads auto --thread-input --aud --progress --no-dct-decimate --no-psnr --no-ssim --output "output" "input"

Basically, I want to get almost "transparent" quality from my encodes so I use CRF 16 and I don't use Trellis since it's CRF and I don't care about filesize. I don't see any difference in quality between Subpixel Refinement 5, 6 or 7. Lastly, I set Adaptive B-Frames to 1 - Fast and B-Frame Mode to Spatial since iI'm encoding animated content.

Are my eyes missing something? I don't see how going above (not below) Subme 5 or M.E. Multi-hex increases quality and I don't see the benefits of Trellis except for Two-Pass and a lower filesize.

Are there any quality benefits in settings like Trellis, mode 2 B-frames, and higher Motion Estimation values?

[Tofusensei]

i7 imo

-Tofu

[Dark Shikari]

Originally Posted by lubczyk

Fast h264 encoding settings?

I just want to encode my anime quickly so that I can get ti doen faster. I don't mind a bigger filesize if the quality doesn't degrade too much. This is the commandline that I get from megui:

program --crf 16.0 --level 4.1 --ref 5 --mixed-refs --no-fast-pskip --bframes 3 --weightb --deblock 1:2 --subme 5 --partitions p8x8,b8x8,i4x4,i8x8 --8x8dct --ipratio 1.1 --pbratio 1.1 --vbv-bufsize 24000 --vbv-maxrate 24000 --qcomp 0.5 --me umh --merange 12 --threads auto --thread-input --aud --progress --no-dct-decimate --no-psnr --no-ssim --output "output" "input"

Basically, I want to get almost "transparent" quality from my encodes so I use CRF 16 and I don't use Trellis since it's CRF and I don't care about filesize. I don't see any difference in quality between Subpixel Refinement 5, 6 or 7. Lastly, I set Adaptive B-Frames to 1 - Fast and B-Frame Mode to Spatial since iI'm encoding animated content.

Are my eyes missing something? I don't see how going above (not below) Subme 5 or M.E. Multi-hex increases quality and I don't see the benefits of Trellis except for Two-Pass and a lower filesize.

Are there any quality benefits in settings like Trellis, mode 2 B-frames, and higher Motion Estimation values?

Quality and bitrate are equivalent. 20% higher quality at the same bitrate means--equivalently--20% less bitrate at the same quality (roughly).

If you just need fast encoding, try:

--qp 18 --deblock 1:1 --subme 1 --partitions none --me dia --no-cabac --threads auto

Also, seriously, stop adjusting ipratio/pbratio/qcomp. Leave those at defaults. And don't use VBV when you don't need it! I can't figure out why people keep messing with obscure settings--do they think that the developers are dumb and can't pick reasonable defaults or something?

[TheFluff]

if you want fast encoding maybe you should think twice before using a setting called "no fast <thing>"

hth

[lubczyk]

Originally Posted by Dark Shikari

Quality and bitrate are equivalent. 20% higher quality at the same bitrate means--equivalently--20% less bitrate at the same quality (roughly).

If you just need fast encoding, try:

--qp 18 --deblock 1:1 --subme 1 --partitions none --me dia --no-cabac --threads auto

Also, seriously, stop adjusting ipratio/pbratio/qcomp. Leave those at defaults. And don't use VBV when you don't need it! I can't figure out why people keep messing with obscure settings--do they think that the developers are dumb and can't pick reasonable defaults or something?

But there's just so many numbers. They all have to mean something!!!

[Soichiro]

They do mean something, but you shouldn't mess with them unless you know what they mean and have a reason to change them.

[lubczyk]

Ok, I've settled on something like this:

program --qp 16 --level 4.1 --ref 8 --mixed-refs --deblock 1:2 --no-cabac --subme 1 --partitions none --me dia --threads auto --thread-input --aud --progress --no-psnr --no-ssim --output "output" "input"

I've found that multiple reference frames really improve overall image quality during playback, so I stuck those in there.

[TGEN]

Originally Posted by lubczyk

I've found that multiple reference frames really improve overall image quality during playback, so I stuck those in there.

Then you can drop the --level 4.1 too (and bump it to 16).

[Dark Shikari]

Originally Posted by lubczyk

Ok, I've settled on something like this:



I've found that multiple reference frames really improve overall image quality during playback, so I stuck those in there.

Mixed-refs doesn't even do anything with partitions none...

[Soichiro]

And 16 refs is a waste of time either way, even on anime. (IIRC ref frames increase time exponentially (or at least linearly) the higher they get, and benefit increases logarithmically, so the more you add, the less benefit you get). 8 is the highest I'd go, especially if you're using completely horrible (fast) settings on everything else.

[Dark Shikari]

Originally Posted by Soichiro

And 16 refs is a waste of time either way, even on anime. (IIRC ref frames increase time exponentially (or at least linearly)

Linearly, and that's only of the time spent on the motion search. At least with me dia/subme1, that isn't much time, though I agree with such low settings its a tad silly.

Originally Posted by Soichiro

the higher they get, and benefit increases logarithmically, so the more you add, the less benefit you get). 8 is the highest I'd go, especially if you're using completely horrible (fast) settings on everything else.

For anime, I find the benefit becomes almost linear after the first few refs (~1% more compression for each ref after ~6).

[checkers]

That deblock is quite high. Not that it will really matter for such a low CRF, but still...

[lubczyk]

Originally Posted by checkers

That deblock is quite high. Not that it will really matter for such a low CRF, but still...

For hand-drawn animated content, I find that deblock 1,2 gets rid of renegade blocks on large same-color textures quite well.

[Utils]

Originally Posted by Dark Shikari

I can't figure out why people keep messing with obscure settings--do they think that the developers are dumb and can't pick reasonable defaults or something?

That's EXACTLY why we do it. I do it with all programs. If there's a setting I don't understand I Google it to make sure I'm not missing out on something or possibly making it worse. This is especially true of open source software because they usually lack tooltips or a help menu.

[Dark Shikari]

Originally Posted by Utils

That's EXACTLY why we do it. I do it with all programs. If there's a setting I don't understand I Google it to make sure I'm not missing out on something or possibly making it worse. This is especially true of open source software because they usually lack tooltips or a help menu.

But x264 does have a documentation page large enough that people have complained about it being too detailed.

And furthermore, it's one thing to look up what something does--it's another to wildly adjust obscure settings. Just because you know what something does doesn't magically mean it becomes sensible to change it, at least without first dropping by the IRC channel and asking if it's a good idea!

[Utils]

@Dark Shikari
> But x264 does have a documentation page...
Thus proving my point. I hate to repeat myself but like I said, they usually don't have built-in help. And also sometimes the information is vague anyway.


> And furthermore, it's one thing to look up what something does--it's another to wildly adjust obscure settings.
Well, some of us out there like to actually learn new things and will research obscure subjects when we encounter them. By learning about a subject it's no longer obscure, you feel me. I don't understand why you want people to stay ignorant when something interests them. That's not cool :(

> Just because you know what something does doesn't magically mean it becomes sensible to change it...
LOL, I have to repeat myself again? "...Make sure I'm not missing out on something or possibly making it worse." I added emphasis. I'll even reiterate: finding out what something does gives us the knowledge to know whether to leave it alone or change it for our particular function.

Knowledge is power, Dark Shikari.

[fireshark]

You're talking to the x264 developer there

[edogawaconan]

Originally Posted by Utils

finding out what something does gives us the knowledge to know whether to leave it alone or change it for our particular function.

it is not enough.

[TGEN]

I personally don't see anything wrong with people screwing up 'interesting' options. It's part of the learning process.

[comatose]

Originally Posted by edogawaconan

it is not enough.

Coupled with some research (that's trial and error), yes, it is.